A transmission electron microscope (TEM) allows for material analyses of very high spatial resolution. For example, structures with feature sizes of 1 nm or less can be resolved. For this purpose, a so-called TEM-sample must be formed of the material to be analyzed, wherein the TEM-sample is at least in part thin so that electrons of the electron beam generated by the transmission electron microscope can traverse the material. Such thin objects are also referred to as TEM-lamellae and exhibit a thickness of, for example, 100 nm or less. The manufacture of such TEM-samples is elaborate and difficult.
A specific kind of TEM-sample is known from US 2012/0185813 A1, wherein the full disclosure of this document is incorporated herein by reference. An example of a TEM-sample known from this reference is schematically illustrated in FIG. 1. For manufacturing the TEM-sample 101 illustrated in FIG. 1, a cuboid-shaped material-block 103 is cut out of a substrate, wherein the material-block contains the region to be analyzed using the transmission electron microscope. The cuboid-shaped material-block can exhibit thicknesses of 0.1 μm to 500 μm and lengths and widths of 5 μm to 1000 μm, for example. Here, the thickness of the cuboid-shaped material-block 103 is too large in order to be traversed appropriately by electrons in a transmission electron microscope. Hence, a strip-shaped recess is formed in each of two opposing flat sides of the cuboid, wherein the recesses extend at an angle δ of, for example, 45° with respect to an edge of the cuboid such that an angle ε between the directions of extension of the strip-shaped recesses 105 amounts to a value of, for example, 90°. A depth of the recesses 105 is somewhat smaller than half the thickness of the cuboid 103 so that a hatched region 107 in FIG. 1, the region of which the recesses 105 cross and overlap, provides a slight material thickness which is equal to the thickness of the cuboid 103 minus the thicknesses of both the recesses 105. By appropriate forcing of the recesses 105, for example, by removing material using a focused ion beam, it is possible to configure the material thickness in the region 107 small such that the material in the region 107 can be analyzed using a transmission electron microscope.
The TEM-sample illustrated in FIG. 1 has the advantage that, due to the surrounding regions of the cuboid 103, the region 107 of thin material is bared by means of a frame and protected against the deformation, wherein the frame can be attached to manipulators and object mounts without damaging the comparatively fragile thin region 107.
US 2012/0185813 A1 discloses apparatuses and methods for manufacturing a TEM-sample illustrated in FIG. 1. Nevertheless, it is desirable to have further apparatuses and methods available which allow manufacturing of such TEM-samples.